1. Field of the Invention
The present invention relates to pneumatic tires which can prevent uneven wearing at end portions of treads.
2. Related Art Statement
As Pneumactic radial tires capable of preventing uneven wearing at the end portions of the treads are concerned tires are known. Such are described in Japanese Patent application Laid-open No. 61-143,205. In the tires of this type, each of the shoulder ribs provided in the end portions of the tread is divided into two narrow ribs by forming a circumferential groove having given width, depth and interval in the shoulder rib. When this pneumatic tire receives lateral forces, the ground contact pressure is made uniform through lateral deformation of the narrow ribs, so that occurrence of local wear acting as a core of uneven wear can be controlled.
However, in the case of such a tire, since the radially outer portion of the narrow rib is in the same level as the contour line of the tread, that is, since the radially outer portion of the other shoulder ribs not divided is in the same level as that of the center rib, the laterally deformed amount of the narrow rib is substantially the same small value as that of the center rib when the tire receives the lateral forces. As a result, it cannot be said that the effect of controlling the occurrence of the above local wearing is sufficient.